The purpose of this thesis is to investigate what it takes to control a luminaire system via Ethernet. The thesis focuses in two major topics. The first topic examines the theory of Ethernet, TCP/IP and industrial protocols and compares them to the OSI reference model. The second topic focuses on required developing tools and available software. An example system was created using a commercially available development board and an open source TCP/IP stack called lwIP. The results suggest that Atollic TrueSTUDIO should be used as the developing environment. The lwIP stack is revealed to be functionally acceptable. However, due to its documentation and support, it is not recommended for future products. Some potential issues that cannot be solved using bare TCP/IP are identified. The capacity of Ethernet is found to exceed the requirements of a luminaire system.